1. Field of the Invention
This invention relates to implements for digging snow. More particularly, the invention relates to a small, lightweight, portable snow digging device that is easier to store and transport by campers, hikers, skiers, snowmobilers, and others who venture into remote or back-country areas in winter.
2. State of the Art
Small, lightweight shovels for use by campers, hikers, skiers, sportsmen, and the like are well known. Many varieties of these shovels are available, including lightweight models designed specifically as snow shovels. However, those currently known are typically made of a rigid material, and include some sort of rigid elongate handle. This configuration makes these shovels unwieldy and difficult to transport in many instances. For example, a conventional portable snow shovel must normally be attached to the outside of a hiker's pack because of its large/odd shape. Shovel heads made of a rigid polymer material also have a tendency to break if a user attempts to force them into a too small or wrongly shaped storage space, or if the storage container is crushed. There is thus a genuine need for a lighter-weight, portable snow shovel that is flexible and can be easily transported inside a backpack or similar small, soft container.
Some conventional lightweight portable snow shovels incorporate a folding mechanism at the base of the handle. This arrangement allows the shovel to be folded into a more compact shape for transport, but also requires the provision of a complicated latching hinge mechanism connecting the base of the handle to the shovel head. Because the bending stresses in the handle of the shovel are greatest at the base of the handle, such mechanisms tend to be either heavy, complicated, and bulky, or else they are insufficient to handle the possible stresses incurred during use of the implement, and quickly break. There is a genuine need for a lightweight, portable snow shovel that does not present the unwieldy shape of conventional shovels, and does not require a complicated and heavy folding latch mechanism at a handle base.
An elongate handle also presents use problems in certain instances. For example, a winter camper attempting to excavate a snow cave with a conventional shovel will find it difficult to maneuver the shovel in the cramped space inside such a cave, making construction errors or mishaps much more likely. For such applications there is a need for a compact snow shovel that is lightweight and easy to use in cramped quarters.
Conventional snow shovels are also somewhat limited in their manner of use because the rigid, formed shovel head is separated from the hands of the user by the length of the handle, and the shovel head is of a fixed shape. Because of the principles of leverage, the separation of the shovel head from the hands of the user can reduce the effectiveness of the tool in certain desirable operations.
In addition, the fixed shape of the shovel head reduces its versatility. First, from a purely mechanical standpoint, a rigid material formed into a specific shape will have a fixed strength in any dimension. This strength is measured as a function of the moment of inertia of the cross-sectional shape of the shovel head. Additionally, conventional snow shovels have only a single cutting blade of a fixed size and shape. It is well known that the cutting action of blades and the like is partly the result of a given force being applied to a very small area (the edge of the blade) so as to impose a very large stress to the surface the substance to be cut. In the case of snow shovels, the force required to cut into snow of a given density will depend on the surface area of the blade that is brought into contact with the surface of the snow. With a conventional snow shovel having a blade of a fixed length, such a shovel will be adapted to cut snow only up to a certain hardness. When harder, icier snow is encountered, the shovel becomes useless because at some point the user cannot apply sufficient force to generate a cutting stress.
If a user were able to selectively modify the shape of the shovel head so as to increase its moment of inertia, the user could advantageously use such a snow shovel in a wider variety of snow hardness conditions. Similarly, if a user could alter the shape of a blade or select from more than one cutting blade to use, that user could efficiently deal with a wide variety of snow conditions. For example, a broad flat shovel head and long cutting edge would be adequate for shoveling and cutting light or soft snow, and would allow relatively large volumes to be moved with any given motion. On the other hand, the shovel head could be adapted for cutting and shoveling hard packed or icy snow by deforming the head to increase its moment of inertia, and applying a shorter cutting edge, and hence imparting a greater cutting stress, to the surface of the snow.